Affiliation: Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, North Carolina, United States of America. nc28@duke.edu

ABSTRACTStem cell transplantation holds great promise for the treatment of myocardial infarction injury. We recently described the embryonic stem cell-derived cardiac progenitor cells (CPCs) capable of differentiating into cardiomyocytes, vascular endothelium, and smooth muscle. In this study, we hypothesized that transplanted CPCs will preserve function of the infarcted heart by participating in both muscle replacement and neovascularization. Differentiated CPCs formed functional electromechanical junctions with cardiomyocytes in vitro and conducted action potentials over cm-scale distances. When transplanted into infarcted mouse hearts, CPCs engrafted long-term in the infarct zone and surrounding myocardium without causing teratomas or arrhythmias. The grafted cells differentiated into cross-striated cardiomyocytes forming gap junctions with the host cells, while also contributing to neovascularization. Serial echocardiography and pressure-volume catheterization demonstrated attenuated ventricular dilatation and preserved left ventricular fractional shortening, systolic and diastolic function. Our results demonstrate that CPCs can engraft, differentiate, and preserve the functional output of the infarcted heart.

Mentions:
The mouse ESC lines D3 [15] and Rosa26 [16] were stably transfected with DNA constructs allowing the expression of the green fluorescent protein (GFP) under the control of the mouse cardiac specific enhancer element of the Nkx2-5 transcription factor as previously described [14]. Following isolation of 50 colonies (clonal) for each cell line, stably transfected clones were identified and further used based on their capacity to express GFP selectively in the spontaneously contracting cardiomyocyte cell clusters. Mouse ESCs were induced to differentiate in suspension forming aggregates termed embryoid bodies (EBs) and initial detection of GFP coincided with initiation of Nkx2-5 expression on differentiation day 5 (Figs. 1a, b).

Mentions:
The mouse ESC lines D3 [15] and Rosa26 [16] were stably transfected with DNA constructs allowing the expression of the green fluorescent protein (GFP) under the control of the mouse cardiac specific enhancer element of the Nkx2-5 transcription factor as previously described [14]. Following isolation of 50 colonies (clonal) for each cell line, stably transfected clones were identified and further used based on their capacity to express GFP selectively in the spontaneously contracting cardiomyocyte cell clusters. Mouse ESCs were induced to differentiate in suspension forming aggregates termed embryoid bodies (EBs) and initial detection of GFP coincided with initiation of Nkx2-5 expression on differentiation day 5 (Figs. 1a, b).

Affiliation:
Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, North Carolina, United States of America. nc28@duke.edu

ABSTRACTStem cell transplantation holds great promise for the treatment of myocardial infarction injury. We recently described the embryonic stem cell-derived cardiac progenitor cells (CPCs) capable of differentiating into cardiomyocytes, vascular endothelium, and smooth muscle. In this study, we hypothesized that transplanted CPCs will preserve function of the infarcted heart by participating in both muscle replacement and neovascularization. Differentiated CPCs formed functional electromechanical junctions with cardiomyocytes in vitro and conducted action potentials over cm-scale distances. When transplanted into infarcted mouse hearts, CPCs engrafted long-term in the infarct zone and surrounding myocardium without causing teratomas or arrhythmias. The grafted cells differentiated into cross-striated cardiomyocytes forming gap junctions with the host cells, while also contributing to neovascularization. Serial echocardiography and pressure-volume catheterization demonstrated attenuated ventricular dilatation and preserved left ventricular fractional shortening, systolic and diastolic function. Our results demonstrate that CPCs can engraft, differentiate, and preserve the functional output of the infarcted heart.